Reading and projection apparatus



Feb. 13, 1945. v. E. IQRATT A 2,369,248

READING AND PROJECTION APPARATUS Filed July 17, 1942 4 Sheets-Sheet lINVENTOR VER/vEuR EPRA rr ATTORNEYS Feb. 13, 1945. v, T 2,369,248

READING AND PROJECTION APPARATUS Filed July 17, 1942 4 Sheets-Sheet 2 vINVENTOR VERA/EUR E PRATT ATTORNEYS Feb. 13, 1945. v. E. PRATT READINGAND PROJECTION APPARATUS Filed July 17, 1942 I 4 Sheets-Sheet 3ATTORNEYS 1945- v. EQPRATT 7 2,369,248

READING AND PROJECTION APPARATUS Filed July 17, 1942 4 Sheets-Sheet 4INVENTOR VERNEUR E. PRAT 1:

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ATTORNEYS Patented Feb. is, 1945 um'rsoi-srares rArE r OFFICE 2,309,243I 1 ammo AND PBOJECTION Arman-rue I Verneur E. Pratt, l lorwalk, Conn. II Applicat lon July 1:, 1e42, semi No. 451,240

' arranged for projection on a .ilat surface below 8 Claims.

The present invention pertains to improvements. in readlng'andprojection apparatus.

An object of the invention-is .to provide 'im-' proved means by whichprinted matter, data and the like, recorded on microfilm, may bepresented in enlarged form for reading orob-f' servation. Y

Another object is to provide apparatus of the above nature adapted topresent the enlarged image by projection either on opaque or translucentscreens.

A further object is to provide a single device of the above characteradapted to present the enlarged image by downward projection on an.

inclined opaque screen within the casing of the device, by downwardprojection on a suitable- A further object is'to provide an improved'lamp housing and mounting by which undue heat is prevented from reachingthe film.

' ranged for horizontal projection on a wall or.

sectional view in the casing Figure 6 is a vertical partial the planes8'8,/Figure 5,;

Fig'ur "l is a iragmental detail of the adjustable leg mounting means;

Figure'8 is a side elevation of the device arthe like? Figure 9 showsthe device arranged for pro- Jection on the translucent screen, thescreen appearing in elevation through the bottom of substantiallyrectangular horizontal section.

.the casing; and Figure 1018 a rear detail view of the lam housingbracket and its heat-insulating mount- Reierring to Figure 1. thenumeral 28 generally indicates an upwardly tapered casing of having sidewalls 2|, a front wall 22, and a rear wall 28. A translucent screenmember 24 is. hinged on a transverse rod 28 in the lower front corner ofthe casing 28. A small boss or extension 28 on the rear edge of thescreen member 24 is adapted to be swung into and held in La retainingdepression or dimple 21 in the rear casing wall 28. An opaque screen 28is also Another object is to provide a device or the type described,which is cheap, without complicated moving parts, and which is readilyportable.

operate, and well adapted to use by school children,'college studentsand the reading public in general. 3

Other objects and advantages will becomeevident in the course of thefollowing description in connection with the accompanying drawings, inwhich Figure 1 is a'vertical sectional view of a preferred'iorm of theinvention;

Figure 2 is a downwardly directed partial sectional view in the, planeof the film, showing the film holder inserted through the front and rearslots for viewing page images with. their upright axes disposedlongitudinally on the illm A further object is to provide areading-device oi the above type which is compact, simple-to hinged onthe rod. 28 and normally rests by gravity on the top of the' translucentscreen member 24, the opaque screen having an upper surface suitableiorreceiving projected-images.

In normal position as shown, the screens 28' and 28 are inclinedupwardly with respect to the front wall 22, and a large rectangular win-'dow 29 is provided in the front wall through which the upper surface ofthe screen 28 may be readily viewed. When the device is used inalternative positions, as hereinafter set forth,

. one or both screens may be swung upward against the rear of theviewing window 28 in the manner indicated. by; dotted and dashed arcs,Figure 1. Small spring latches 88, se-

curedto the inside of front; wall 22 beside the window 28, 'are providedto catchand hold the translucent screen 28 in its upwardly swungposition, in which position it also holds the.

overlying opaque screen 28. The opaque screen 28 is shorter than screen28,. and. need not en,

gage the latches 20, since whenthe device is ta sectional viewthe topthereof, the plane of plate 3| being par. allel to those of the screens24 and 28 when the latter are in normal. position as shown in Figure 1.A second plate32, also parallel to the normal planes of screens 24 and28, is secured in the casing 20 above and spaced from the plate 3|.

A suitable projection lens system 33 is adjustably mounted in the lowerplate 3| in any suitable manner, for instance by means of a frictioncollar 34. The upper plate is apertured at 33 and carries a condensinglens system 33 in optical alignment with the projection lens 33, theoptical axis of the condensing and projection lens systems beingperpendicular to the normal planes of screens 24 and 28.

A bracket 31, shown in detail in Figures 1 and 10, is mounted above therear top of the upper plate 32 on small posts 38, these posts being madeof any suitable heat-insulating material. A forwardly directed lampsocket, 39 is secured to the bracket 31, and is providedwith a supplycord 43 passing downwardly through plates 32 and 31 as shown in Figuresand 2, and Figurefi, thence outward through rear casing wall 23. Thecord 43 is of any desired length, and terminates in a suitableattachment plug 4|, Figure 6.

The socket 39 holds a projection lamp 42, the filament 43 of the lampbeing disposed in the optical axis of the condensing lens 33.

A housing 44 is detachably secured to the bracket 31 and encloses thelamp 42. The housing 44 comprises inner and outer shells 45 and 43 madeof metal of substantialthickness and preferably colored black. Alignedapertures 41 and scribed light source and related apparatus.

A horizontal slot 53 is provided in the front casing wall 22, and therear wall 23-has a similar slot 54. The upper edges of these slots areflush with the bottom of the top plate 32, and the center line of theslots are in alignment with the optical axis of the lens system,Forwardly and rearwardly directed leaf springs and 53 are secured to thelower plate 3|, these springs being bowed upwardly toward the plate 42in line between the slots 53 and 54. Similar slots 51 are provided inthe casing side walls 2|, these slots being in transverse line with theaxis of the lens system as illustrated in section in Figures 2 and 3.Laterally directed leaf springs 53, similar to springs 55 and 53,.arealso secured to the lower plate 3| in line with the centers of slots 51.

In the preferred form of mounting, a strip of film 59 carrying therecorded images, is held between two slabs of glass 33 and 3|, the slabsbeing secured together by any suitable means such as strips ofCellophane tape 32, Figures 2 and 3. In Figures 2 and 3, however, theupper glass slab 3| is removed in order to permit direct plan views ofthe film strips.

A typical embodiment of such a film strip is .one on which the pages ofa book are photographed, a large number of individual page images 33being included in a normal film frame 34, Figure 2. While for purposesor illustration these small individual images are shown in only one mainfilm frame in order to avoid unduly complicating the drawings, it willbe understood that all the other frames may contain similar numbers ofimages, by which means a very large number of page images amounting toan entire book may be carried on a single short strip of film.

The page images may be arranged with their upright dimensionslongitudinally of the film, as in Figure 2, or with the verticaldimensions laterally of the film, as in the case of images 33a on film59a, Figure 3. In either case it is required that the projected imagesappear upright when viewed by an observer in front of the casing, thefront being the lower side in Figures 2 and 3. In the first-mentionedcase, that is with the longitudinally arranged upright page images, theslabs 32 and 33 holding the film 59 are inserted through the front andrear slots as illustrated in Figures 2 and 1, the insertion being madeof course in the proper position to allow for reversal by the projectionlens 33. The springs 55 and 53 press the glass slab and film stripcombination upward in fiat contact with the bottom of the upper plate32, thus holding the film 53 in a fixed plane between the condensinglens 33 and the projection lens 33. The slots 53 and 54 are sufficientlywider than the slabs 30 and 3| to permit the latter to be shiftedlaterally to bring any desired portion of the film width within thescope of the optical system. Similarly the slabs may be shifted to anydesired longitudinal position. Thus by longitudinal, lateral, orcombined adjustment of the position of the film holder, any desired pageimage may be brought into registry with the lenssystem for illuminationby light thrown thereon by the condensing lens 33 and for projection bythe lens 33. The springs 35 and 53 exert sumcient pressure to hold thefilm holder in any set POsition at all times.

Similarly when the film carries page images orientated as illustrated inFigure 3, the holding slabs and film 390 are inserted through the sideslots 51, thus bringing the laterally disposed page images 3311 intoposition for upright projection. In this case the springs 53 hold theslabs and film in any selected position in themanner previouslydescribed.

From the foregoing description, it will be seen that thestructureprovides simple means for proper projection of either longitudinally ortransversely orientated images without the necessity for rotatableprojection heads or other comparatively complicated and cumbersomestructures involving moving parts and adjustments.

For normal reading, the device stands upright with the screens 24 and 23in inclined position as shown in Figures. 1 and 4, the. operatorobserving the projected image 35 on the opaque screen 28 through thefront window 29. In ordinary upright position the' device stands onsmall feet 33, preferably of rubber or the 1ike,'held in front and rearsocket blocks 31 and 38 secured in the bottomcorners of the casing 23.

Each of the two rear socket blocks 38 has'an inclined hole 39 extendingtherethrough from top to bottom. Each front block 31 similarly has anup-and-down inclined hole 13 but also has an intersecting horizontalhole shown in detail sectional Figure 7, this latter hole extendingthrough the front plate 22. Clamping screws 12 provided with exteriorknobs 13 are threaded into the front blocks 31 at the intersections ofholes 10 and II therein. Similar clamping means 14 are provided for therear blocks 38.

When a is desired to project a large image on a flat surface such as atable below the device, the

feet 66 are removed from blocks 61 and 68, and

back of the window 28. Extefision legs 15, Figures lathe screens 24 and28 areswung up against the 5 and 6, are inserted in the holes 89 and andclamped therein by operating the exterior knobs tion as shown in Figure6, the image is projected through the bottoinof thecasing. the) surface16 with an increased enlargement "dependent on the additional heightprovided by the extension legs 15. The, laterally outward inclination ofthe legs prevents any interference thereby with the cone 'of projectionand allows unobstructed view of the projected image. Obviously the legs15 may be madebf suitable length to allow any desired degree ofenlargement, the latter being limited only by the focal capacity of vthe lens and power of the lamp used.

It will be noted in Figures 1 and .6 that two additional socket blocks11 are provided in the upper front corners of the casing. 20. Theseblockshave substantially horizontal holes 18 extending through the frontwall 22. The purpose of provision is as follows:

When it is desired to use the device for projecting horizontally againsta vertical wall or screen 18, Figure 8, the screens 24 and 28 are swungup to inoperative position as described aboveholes 18, while the frontlegs 8| may be moved to anydesired position. in the blocks 61 and lockedtherein by the clamping knobs 13, thus providing projection against thewall 18. Since both the interior screens 24 and 28 lie fiat in the frontof the device as shown in dotted lines in Figure 8,

they are clear of the cone of projection, and pro-' means to adjust'theposition of the device on the table 82 to assure the correct desiredangle ofjection to the wall 18 takes place through the bottom of thecasing 20 without obstruction.

When it is desired to observe micro-filmed data by. projection on thetranslucent screen 24, the

device is arranged in substantially the same manner as described abovefor horizontal exterior projection, except that the screen 24isswungupward into its normal position in retaining engagement with thedepression or dimple 21 as shown in Figure 9, and the legs 8| may beadjusted to tip the lower end of the casing 20 upward, thus. incliningthe screen 24 at a convenient angle for easy viewing. In this positionthe opaque screen 28 rests flat by gravity against the inside of thefront window 28, so that unob= structed projection takes place from thelens 82 to the translucent screen 24.

A handle 88, Figures 1, 6 and 8, is provided on the back of the-casing20 to facilitate carrying the device and arranging it in any of thepositions described.

v The device may be focussedby manually moving the projection lenssystem 22 in ltssleeve 34,

' the operator inserting his hand either through I whereby saidprojecting means may project an I and bracket 31.

the bracket 31 and its. attached light-source the bottom of the casing28 or through the window 28, depending on which of the describedarrangements of the apparatus is to be used.

During projection substantially all the'radiant heat from the lamp 42,except that necessarily directed through the light apertures 41 and 48,is rapidly absorbed by the closely enveloping inner housing sleeve 45,from which latter the heat is conveyed by a combination of radiation,convection and transmission to the outer sleeve 4i Since the entiremounting of structures is through the insulating posts 38, practicallyno heat can be transmitted directly to the plate 32 and attachedstructures, so that the heat is dissipated from the bracket and lamp-housing principally by convection and partly by radiation to' tlieho0d-5|- and through the perforations 52 to the outer atmosphere. Due ton.

the free ventilating provision and large surface of the hood 5|, heatintercepted-thereby is rap-- idly given up to the atmosphere with theconsequence that any heat transmitted from the hood to the casing 20 issmall in amount and dissipated, over a large area. By the provision ofthe above structures and arrangements, the

heat finding its way to the film 59 is practically negligible except forthat due to the direct illumination, and even .this' latter heat israpidly dissipated by the comparatively heavy glass slabs i0 and 8|.Thus the device may be operated continuously with a lamp 42 of amplepower without sufllcient rise in temperature to endanger the film orinconvenience the operator. The advantage of this feature is obvious,particularly in such cases as operation by school children or 1 otherinexperienced persons.

During projection on the translucent screen 24 as shown in Figure 9, theopaque screen 28 acts substantially as a closure for'the window 28, thuspreventing extraneous light from entering to fog the image. Similarly,during exterior projection the screen 29 acts substantially as a closureagainst light passing 'either inward or outward. a From the foregoingdescriptionit will be seen While theapparatus has been described inpre-.

ferred form it is'not'limited to the precise struc-' tures set forth, asvarious modifications may be made without departing from the scope ofthe pp nded claims. What is claimed is: v v a 1. In a device of thecharacter described, an

upright casing having an open bottom and a viewing window in the frontof said casing, a

. translucent screen within the bottom of said casing, an opaque screennormally overlying said translucentscreen, means in said casing toproject an image on said opaque screen, said image being viewablethrough said window, and hinging means connecting said opaque screen tosaidcasing to permit'said opaque screen to be swung against the back ofsaid window and out of the path of projection of said projecting -meansimage on said translucent screen, said last named image being viewablethrough the bottom of said casing andsaid opaque screen forming substan-4 aseaaca tially 3, am msaid window whereby eminetom to an exteriorsurface.

- 3. The invention claimed in claim 1 including means to space saidcasing above a supporting surface, and wherein 'means are provided forhinging said translucent screen at the hinging means for the opaquescreen in said casing, adapting said translucent screen to be swungclear of said path of projection, whereby said projecting means mayproject an image through said bottom on said supporting surface, saidtranslucent screen holding said opaque screen against the back of saidwindow.

4. In a projecting device, in combination, a plate, having an aperturetherethrough, a light condenser secured to one side of said plate inalignment with said aperture, a light source spaced from said condensinglens in optical alignment therewith, a radiant heat intercepting housingabout said light source, said housing having a light aperture in linebetween said source and said condenser, a means including bracketholding said source and said housing in cooperative relationship, andheat-insulating means connecting said bracket and said plate,

said heat-insulating means comprising the en- ;tire supporting means forsaid bracket, hous and light source on said plate.

5. The invention according to claim 4 where- 5 in said heat insulating.means comprises posts of material having low unit'heat transmittinability and small cross sectional areas.

' 6. The invention according to claim 4 including means to position afilm holding means on the other side of said plate in operative registrywith said aperture, condenser and light source.

7. The invention according to claim 4 wherein said plate is secured toone end of a casing,

and including a hood of large superficial area secured to said casingand enclosing said light source, housing, and condenser, said hoodhaving a plurality of ventilating openings therein.

8. In a projector, in combination, a light source, a housing closelyenveloping said source and including heat absorbing, transmitting andemitting inner and outer shells, said shells having staggeredventilating holes therein, a supporting plate, heat insulating meanssecured to said plate, a bracket secured to said heat insulating meansand spaced thereby from said plate,

said bracket also supporting said light source and said housing wherebysaid insulating means form a unitary support for said bracket, saidsource andv said housing, means forming aligned light apertures in saidshells and a. condenser supported on said plate with its axis inalignment with said apertures and said light source.

VERNEUR E. PRA'I'I.

